Nanette Must Pass Through Three Doors as She Walks from Her

Multiple Choice

Nanette must pass through three doors as she walks from her company's foyer to her office. Each of these doors may be locked or unlocked.
Let C be the event that at least two doors are unlocked. List the outcomes of
"L" designate "locked" and U" designate "unlocked".]

A) {LLL, LLU, LUL, LUU, ULL, ULU, UUL, UUU}
B) {UUU, LUU, ULU, UUL}
C) {LLU, LUL, ULL, LUU, ULU, UUL}
D) None of these.